User's Manual

Bluegiga Technologies Oy
Page 29 of 41
12 Layout Guidelines
12.1 WF111-A
Figure 13: Recommended layouts, on board corner and on board edge
See figure 13: recommended layout for the suggested module layout. The impedance matching of the
antenna is designed for a layout similar to the module evaluation board. For an optimal performance of the
antenna the layout should strictly follow the layout example shown in figure 8 and the thickness of FR4 should
be between 1 and 2 mm, preferably 1.6mm.
Any dielectric material close to the antenna will change the resonant frequency and it is recommended not to
place a plastic case or any other dielectric closer than 5 mm from the antenna.
ANY metal in close proximity of the antenna will prevent the antenna from radiating freely. It is recommended
not to place any metal or other conductive objects closer than 20 mm to the antenna except in the directions
of the ground planes of the module itself.
For optimal performance, place the antenna end of the module outside any metal surfaces and objects in the
application, preferably on the device corner. The larger the angle in which no metallic object obstructs the
antenna radiation, the better the antenna will work.
DO NOT place WF111-A in the middle of the application board. Even with a board cutout around the
antenna the range will be bad.
The three pads on the antenna end of the WF111-A can be connected to the ground or left unsoldered.
12.2 WF111-E
RF output can be taken directly from the U.FL connector of the module, and no antenna clearances need to
be made for the module. The three pads on the antenna end of the module can be connected to the ground or
left unsoldered.
12.3 WF111-N
Antenna connection is routed to pad 31. Pads 30 and 32 beside the antenna connection should be properly
connected to the ground plane. No antenna clearances are needed for the module itself. The antenna trace
should be properly impedance controlled and kept short. Figure 14 shows a typical 50 ohm trace from the RF
pin to a SMA connector.